• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1391-1398
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• 2011

Biomechanical analysis of arm motion during steering was performed using a motion analysis technique. Three-dimensional position data for each part of arm are fed into an interactive model combining a musculoskeletal arm model and the mechanical steering system to calculate joint angles and torques using inverse kinematic and dynamic analyses, respectively. The analysis shows that elbow pronation/supination, wrist flexion/extension, shoulder adduction/abduction, and shoulder flexion/extension have significant magnitudes. Sensitivity analysis of the arm joint motion with respect to seating posture and steering wheel configuration is carried out to investigate the qualitative influence of the seating posture and driver's seat configuration on the steering behavior.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.12 no.1
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• pp.1-9
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• 2018

This study is intended to identify how horseback riding affect the bone density of the elderly. A total of 31 normal senior citizens participated in the research, who were randomly divided into two groups: 15 in horseback riding exercise group and 16 in horseback riding machine exercise group. A horseback riding exercise program was carried out for 25 minutes twice a week for 12 weeks. A pre-test was conducted before starting the program and two post-tests were conducted 6 weeks and 12 weeks after exercises in the same way as the pre-test. Measured items were bone density of lumbar vertebrae and femur. In order to identify the changes in measurement variables before exercises and 6 weeks and 12 weeks after exercises, two-way repeated analysis of variance were used. The comparison of changes in the bone density in both groups revealed that there were significant differences in lumbar vertebrae L3, L4, femur trochanter in both groups over time. This study suggests that three-dimensional movements of horses through horseback riding exercises induce normal movements of senior citizens, providing positive effects on their bone density. If appropriate horse riding exercise programs are used considering the health status, time and economic conditions, and preferences of senior citizens, it would improve their quality of life.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.4 no.1
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• pp.53-61
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• 2010

In this paper, We investigated the characteristic analysis of flexibility and muscle strength for exercise to verify capacity in rehabilitation exercise of lumbar using lumbar strengthen exercise instrument. We have experiment in 20th years man and woman who are 20 subject with no medical history, we divided subjects into control group with no exercise and training group with lumbar strengthen exercise. We used Hi-Spine(Medicalscience.korea) also, provided exercise 40 minute a day, three days a week and progressed total four weeks. Moreover in our experiment, subjects exercised four postural position as lay down, sit, stand and stretch each ten minute. We measured trunk extension backward, trunk flexion forward, evaluation of based physical fitness and lumbar joint torque. The reults have shown that there more improved all for flexibility, based physical fitness and lumbar joint torque in training group than control group. We indicated that by rotating 3-D axis movement flatform of exercise instrument, muscle spindle in subject have been stimulated and these rotation direction and angle caused muscle tonus and contraction that makes muscle, flexibility and based physical fitness improve more. Our study can be used rehabilitation exercise program to aged people and patient with lumbar injury.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.145-150
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• 2020

The ship motion of large LNG ships affects ships' safety. The purpose of this study was to estimate the transfer function of roll motion among the hull motion of 153,000 m3 class LNG vessels. The ship motion transfer function was modeled using a Linear Time-Invarient system with single input, single output, and transfer function. The transfer function of the ship motion was estimated by the system identification method using single ocean wave as input of the model, and using the roll motion of the LNG ship obtained through ANSYS as the output of the model. The usefulness of the experimental results was evaluated using the precision and estimation rate of the model for cases wherein the different transfer function dimensions. Results of the experiment showed a precision at 99% and 98%, with estimation rate at 78% and 50%. From these results, we found the proposed method of estimating the transfer function of ship motion in this study reasonable. In the future, data of ship motion in actual sea conditions will be acquired and it will be applied to make the construction of models with multiple inputs and multiple outputs for practical use.

• Journal of the Korea Computer Graphics Society
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• v.5 no.2
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• pp.43-52
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• 1999

In this paper, we present an animation toolkit based on motion mapping technique in a graphics user interface that can represent data structures necessary for generating character motions. The motion mapping means that an animation sequence generated once can be mapped to another object directly according a data structure in the graphics user interface. Users can generate animation sequences interactively using a mouse. These are obtained automatically by modifying motion data structures interactively. Compared with other conventional tools, the toolkit has different features that two hierarchical structures necessary for representing modeling and animation data are managed independently each other, and that animations generated can be applied to any other characters by connecting the two hierarchical structures in the user interface.

• Journal of the Korean Society for Railway
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• v.15 no.1
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• pp.1-8
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• 2012

Wheelset dynamic analysis is a key element to determine the degree of accuracy of railway vehicle dynamics. In this study, a three-dimensional wheelset dynamic analysis is presented in such a way that the precise wheel-rail contact analysis in three-dimension is implemented into the dynamic equations of a wheelset. A numerical procedure that can be used for the analysis of a wheelset dynamics when the wheel-rail two point contact occurs in a cornering maneuver is developed. Numerical solutions of the constraint equations and the dynamics equations of a wheelset are achieved by using Runge-Kutta method. The proposed wheelset dynamic analysis is validated by comparison against results obtained from VI-RAIL analysis.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.187-197
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• 2015

The purpose of this study is to analyse the convergent factors which influence on the stages of exercise behavior change of middle-aged women. 200 middle-aged women surveyed, 41 to 64years old, is residing D city, Chung-Nam province, who understand the purpose of this study and agree to participate in this study. This study data is analyzed by using frequency, percentage, standard deviation, t-test, $x^2$ test and Logistic regression analysis. The study show that the social support factors(${\beta}$=.998, p=.010) and the motives of exercise(${\beta}$=3.407, p<.001) among middle aged women have an effect on the stages of exercise behavior change meaningfully. That is, the social support of middle aged women who have exercise behavior change is 2.5 times higher than middle aged women who don't have exercise behavior change, and the motives of exercise is 20.1 times higher. Based on theoretical ground, this study suggests that government and community seek programs for promoting the exercise behavior, considering the motives of exercise and the social supports.

• Journal of Life Science
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• v.22 no.3
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• pp.312-317
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• 2012

The time-dependent effects of highly intensive exercise on the hematological properties of leukocytes, as well as $CD4^+$ and $CD8^+$ level changes as T-lymphocyte activation subsets and the cell death of lymphocytes in rats were studied in this research. Twenty, 60, and 120 min of highly intensive exercise was performed daily for 8 weeks. Total leukocyte counts in the blood of rats exercising for 20 min were elevated; they then decreased to less than the level of the control group up to 120 min. The patterns of lymphocyte level changes were directly influenced by exercise duration and the extents of alteration were similar to the total leukocytes counts. The levels of $CD4^+$ and $CD8^+$ in the blood of the exercising rats were not statistically different even when the exercise was continued for 120 min; thus, the exercise did not affect T-lymphocyte activation. Early- and late-stage lymphocyte apoptosis was not affected by the length of exercise, except that late-phase apoptosis was slightly increased at 120 min, suggesting that aging processes for lymphocyte apoptosis might be stimulated at that time. As the exercise time became longer, stimulated necrosis of lymphocytes was observed, so damage in lymphocytes and a potential loss of immunity might be presumed. The current observation suggests that long-term, highly intensive exercise might result in a loss of immunity that could be due to the damage of lymphocytes in terms of both their numbers and inflammation-related functions. The results suggest that under highly intensive exercise conditions, more than 20 min of exercise should not be suggested for health care purposes.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.98-98
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• 2012

최고진공도 10-10 mbar, 배기속도 2500 L/s를 구현할 대용량 복합 분자펌프(TMP) 설계를 위한 3차원 유동해석을 실시하였다. 진공도가 10-5 mbar 이상이 되는 고진공도에서는 Knudsen 수가 102~107에 이르러 분자간 충돌을 거의 무시할 수 있게 되며, 이때의 유체해석 방법으로서는 통상 희박기체 해석법으로 많이 쓰이는 Direct Simulation Monte Carlo (DSMC) 방법이나 Continuum fluid에 대한 Navier-Stokes 해석보다, 충돌이 없는 분자의 자유운동을 모사하는 Monte Carlo 방법이 더 적합할 수 있다. 본 연구에서는 다단계 rotor와 stator로 구성되는 복합분자 내 유동장에 Monte Carlo 해석법을 적용하여 유동해석을 실시하였다. 해석 방법의 타당성을 확인하기 위해 동일한 형상에 대해 Navier-Stokes 해석과 DSMC 해석을 병행하였다. 각각의 수치적 해석에서 공통적으로, TMP의 성능에 지배적인 영향을 미치는 설계변수는 rotor-stator의 날개각임이 확인되었고, 이 설계변수들의 최적값을 다양한 3차원 유동해석을 통해 도출하였다. 해석결과는 펌프설계에 적용되어 펌프 성능시험결과를 통해 확증된다.

• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.34-37
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• 2009

Deforming mesh should be used when bodies are deforming or moving relative to each other due to the presence of aerodynamic forces and moments. Also, the flow solver for such a flow problem should satisfy the geometric conservation law to ensure the accuracy of the solutions. In this paper, a RANS(Reynolds Averaged Navier-Stokes) solver including automatic mesh capability using TFI(Transfinite Interpolation) method and GCL is developed and applied to flows induced by oscillating wings with given frequencies. The computations are performed both on deforming meshes and on rigid meshes. The computational results are compared with experimental data, which shows a good agreement.